1. Description of the Prior Art
Reference is made to U.S. Pat. No. 1,788,561 by A. H. Boettcher dated Jan. 13, 1931 which shows a player piano employing an electric motor roll drive, and application Ser. No. 465,305 filed Apr. 29, 1974 by Luther S. Joy which shows and claims an electro- pneumatic player piano employing a semi-automatic transmission.
2. Field of the Invention
In recent years the popularity of player pianos has increased to the point where "rebuilders" are no longer able to acquire a sufficient number of old pianos to meet demands. As a consequence several companies have investigated the feasibility of building player actions for modern pianos. A paramount problem with such an undertaking lies in the fact that the conventional player action occupies a large volume within the piano case. It is therefore not possible to incorporate such units in modern small case spinet pianos. In addition to their bulkiness, the traditional player action requires considerable pumping effort. Moreover, the large vacuum reserve which was required for smooth continuous operation of the air motor and pneumatics produced a long time constant for the vacuum system. This resulted in a consequent decrease in the expression capabilities of the action and thus diminished the interactive aspect between human and machine. Another obstacle to the manufacture of a modern player action lies in the tremendous increase in the cost of labor. What is actually desired is a high quality player action which can be profitably built using present day technology and materials, and easily installed within the confines of a modern piano case.
An object of the present invention is to provide an electric motor which is coupled to the roll through a novel transmission which automatically engages and disengages the take-up and rewind spools in response to sensing switches which detect the presence of vacuum as well as the beginning and end of the roll on the take-up spool. In addition, it is desirable that the transmission automatically shift from the play mode to the rewind mode when the end of the roll is detected -- and that it automatically shift from the rewind mode to the play mode when the rewind operation is complete. Another object of the invention is to provide for automatic shut off after the transmission has completed its cycle and returned to the play mode.
An ancillary feature of the present invention lies in the connector system which enables the tracker bar vacuum hoses to be quickly connected and disconnected from the pneumatic stack. The entire pneumatic stack can thus be quickly removed for repair, and then reinstalled without disturbing the hose connections.
An additional object of the invention is to provide a manual pneumatic pump for actuating the notes, and an electric motor for operating the roll. Although primarily intended for a manual operation, it is a further object to include a separate vacuum motor for operating the stack if fully automatic play is desired.
Another object of the invention is to provide a pneumatic stack which is designed to permit access to all bleed holes.
Other objects and advantages of the present invention will be obvious from the detailed description of a preferred embodiment given herein below.